The development of wing-flapping will be studied in domestic chickens (Gallus domesticus) using stroboscopic, cinematographic and electromyographic procedures. The proposed research will provide a rigorous quantitative disruption of wing-flapping from the time of hatching until 3 weeks of age, at a time when the wings are well feathered and the young bird is capable of adult-type wing-flapping. Since successful wing-flapping depends upon the synchronization of motor outflow to both wings, the study also deals with the broader issue of the development of between-wing coordination. The results will provide descriptive control data for subsequent experimental studies which will attempt to define the neuronal mechanisms and experiential variables which are involved in the development of bilaterally coordinated wing-flapping. Such studies should advance our understanding of the neurobehavioral mechanisms involved in the development, production and control of normal and abnormal bilateral coordination in many vertebrates including man.